Answer:
lithium
Explanation:
this is because lithium has a valency of 1 and oxygen has a valency of 2 thereby exchanging valency to create Li²0
We are given the following equation:
y = y0 e^-0.0001216 t
where y = 1/5 y0, y0 is the original amount
So solving for time t:
1/5 y0= y0 e^-0.0001216 t
t = 13,235.51 years
So the human died about 13235.5 years ago
Answer:
KOH and H₂SO₄
Explanation:
Neutralization reaction:
It is the reaction in which acid and base react with each other and produce salt and water.
For example:
2KOH + H₂SO₄ → K₂SO₄ + 2H₂O
1. Potassium hydroxide and sulfuric acid react to produce potassium sulfate salt and water.
2. Potassium hydroxide and phosphoric acid react to produce potassium phosphate and water.
H₃PO₄ + 3KOH → K₃PO₄ + 3H₂O
3. Phosphoric acid sodium hydroxide react to produce sodium phosphate and water.
H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂O
1.
V = 200 mL (volume)
c = 3 M = 3 mol/L (concentration)
First we convert mL to L:
200 mL = 0.2 L
Then we calculate the moles using the formula: n = V × c = 0.2 L × 3 mol = 0.6 mol
Finally, we just use the molar mass of CaF2 to calculate the actual mass:
molar mass = 78 g/mol
The formula is: m = n × mm (mass = moles × molar mass)
m = 0.6 mol × 78 g/mol = 46.8 g
2.
For this question the steps are exactly like the first question.
V = 50mL = 0.05 L
c = 12 M = 12 mol/L
n = V × c = 0.05 L × 12 mol/L = 0.6 mol
molar mass (HCl) = 36.5 g/mol
m = n × mm = 0.6 mol × 36.5 g/mol = 21.9 g.
3.
The steps for this question are the opposite way.
m(K2CO3) = 250 g
molar mass = 138 g/mol
n = m ÷ mm = 1.81 mol
c = 2 mol/L
V = n ÷ c = 1.81 mol ÷ 2 mol/L = 0.905 L = 905 mL
